Spark-plug.



J. T. NORMAN.

SPARK PLUG.

APPLICATION man ma. 2. 191:.

1,243,205. Patented Oct. 16, 1917.

' constructed pl'ug'in which the-inner- UNITED TAT- s PATENT OFFICE.

JOSEPH '1'. NORMAN, 0F NAN'I'ICOKE, PENNSYLVANIA srAnK-rLUo.

. Specification of Letters Batent.

ratented 0015.16, 1917.

Application llledfebrnary 2, 1915.; Serial No. 5,717;

16 electrode in place.

' A further chest of the in'vcntio'n'is to provide means w er'eby the plug points are kept from fouling, by oil' on" carbon deposits, as much as possible.-

In itsgencric naturelthe invention comprises an outer threaded section" adapted to be screwed in thefspdrlr plug 0 nmg of an internal combustion engine, on dorm one ofthe electrical connections. the threaded Fig. 5 is a detail band by means of w secured in place.

Fig. 6 is a cross section of Fig. l.

ich the screen may be erspective view of the;

on the line S-[ 6 60 Fi 7 is a view similar to Fig. 1, showinga slig t modification of the invention.

Fi 8 is aview similar to Figs. 1 and 7, showing a furthermodification.v

Fi 9 ismcross section on the line 9-9 of'Fig. B. i m- Fig. 10 is an elevation ertly in section, showing a .further modi cation of spark plug.

In'the drawin in wihich-like numerals and letters "of re erence indicate like parts;

socket section carryingthefsparking point i and serving ash holder or retainer for the inner elctrodeor sparkifiif point, the inner electrode being ojirode form and m. bedded 1n a mess whi'chfills. the outer see tion and is itself cpmp'osed b flaicementitious the oil 40 in'placc preferred fern composition so. as to .7 Secure the inner electrode in hoenix} cfiet-a tight joint the projecting points of the plug being protected b a screen which serves; tqfrestrain om splashing by virtue of carbon deposits. r

The improvedplug also includes an upwardly extending section of heat insulating material the same being preferably secured by a cap nut threaded onto the inner electrode. 1 In its more subordinate nature, the invention also includes these novel details of constructiomcombination and arm ement of parts all of which willbe first fully ascribed, then be specificslgointed out'in the appended claims, an i ustrated in the accompanymg drawing, in whichz- Figure 1 is a ongitudinal section of the l of the invention. detail perspective view of a the screen being omitted. tion on the line 3-3 Fig. 2 is a portion of the same, Fig. is n 'cmsssec of Fig. 1.

Fig. 4 is a detail perspective view of the 301130".

in all of the figures, 1 re resents the outeror socket seetionof theug which isof the usual construetionan is provi wrench receiving face and 'with the threaded (led \vithm.

portion 2.-that is ,adapted toenterthe sparkplug-opening of an i gine. In the-preferredform, member also includes an extension sides of which-areremoved tqileave S160 nternal combustion en- ;the socket 3,. the

openings 4 'for: the admission of the combustible'chargetothe spark gap;

5 designates'tbepin which extends across and is in electrical-engagement-with the extension '3, so as to be electricnllygrounded to thecngine casting, end 6 reprcscnts'thccenter, electrode-wh ch is refcra'blyprovided.-=--vvith -eshoulderl 7 on e chisel-shaped pin 5but s'paced"fr om these-motto f orm the Park'g P.

The inner e in the form shown in nently embedded in a filler 9 that is placed in the shell or ,outer. socket member of the plug. strueted of a composition of cement and asbestos to form not only a. rigid holding medium but an insulating medium as well and affords a permanent connection between the center electrode 6 and the pin electrode 5. l

The inner electrode 6 extends upwardly through a wooden shank 10 that is provided with olprojection 10" to' enter" the upper portion of the metallic shell 1 and a second projection 10 over which the screw cap 11 is fitted, the capll being threaded onto the stem of the inner electrode 6 to hold the wooden section 10 in place, the wooden section 10 serving as a heat insulating medium ectrode is;

in the nsu n1 manner,

end .8, Isdjacenjtjo, the

Figs. v1 to 7, perma.-

This filler member is preferably conby which the spark plug can be handled when hot. i

12 is the usual milled nut, by means of which the connectin wire from the ignition circuit may be attac ed to the electrode 6.

13 is a screen cup that is fitted over the sparking end 3 of the outer shell to inclosc the electrodes at the spark gap and prevent the cylinder oil from fouling the points, thus reducing the danger of carbon deposits. Any oil that may accmnulate on the screen 13 will be blown off by the ex losion of the gases within the screen ,at he instant of ignition.

The form shown in Fig. 7 differs from the form shown in Fi 1 'in that the extension and 3 of the shell is omitted and the pin 16 is of the L-type threaded at 17 into the shell so as to be susceptible of being turned out,

as shown in dotted lines in Fig. 7, .when it is desired to test the inner electrode 6.

If desired, one or more mica disks 19 can be'interposed betwecn the shoulder 7 and the metallic parts of the shell 1, although 1 believe that such use of mica will be unnecessary. p

In the form shown in Fig. S,'the central electrode 6 is screwed intoa sleeve 18 that is embedded in the filler 9 and thuselectrmle 6 maybe adjusted to change the length of the spark gap by simply turning the electrode (3 within the sleeve 18, after loosening up the nut 11.

From the foregoing description taken in connection with the accompanying drawing, it is thought the complete construction, operation and advantages of my invention will be readily understood b those skilled in the art to which the invent-ion relates.

Fig. 10 illustrates a further modification of construction of my spark plug in which the electrodes 5 and 21 are confined within the compass of the metallic-body of the plug, the electrodes 21 being firmly embedded in the metal of the plug and are exposed at openings 20. A cement filling 9 is applied to the interior of the plug as shown, leaving the electrode points exposed.

What I claim is:

1. In a spark plug. an outer shell having a wrench receiving upper end. and a threaded section to enter the spark plug opening of an engine, an inner electrode. said inner electrode comprising a threaded rod extending above said shell. a heat resisting insulating filler within said shell. and embedding a portion of saidrod to retain said shell and rod in permanent relationship, said shell and said rod projecting beneath said filler, a. pin carried by said shell to cooperate with the lower sparking end of said rod to form the. spark gap, and a screen inclosing said pin and said inner electrode end at the spark gap to protect the same.

2. A spark plug comprising a shell adapted to be threaded into the spark plug opening of an engine, a pin carried by said shell, an inner electrode comprising a threaded rod entering said shell and projecting upwardly from the same a filler of heat resisting electrically insulating material within said shell around said inner electrode, a heat insulating extension on said inner' electrode in engagement with the upper end -,of i

said shell, a threaded cap on said inner electrode to retain said heat insulating extension in place, a milled nut on said inner electrode to coiiperate with said cap for securing a circuit wire to the same, a screen cup secured on said shell over the sparking.

points to protect the same from fouling, and a threaded sleeve surrounding said inner electrode and in threaded en agement with the same and embedded in said heat resistinginsulating filling.

, JOSEPH T. NORMAN. v Witnesses:

Ron'r. B. Jon, H. M. MORGAN. 

